Biology Protein Synthesis

RNA

Macromolecule - made of nucleotides; sends genetic information

Ribosome

A cell structure that is the site of protein synthesis

Mitochondria

A cell structure that is the site of ATP (energy) production

mRNA

Messenger RNA - brings genetic information to ribosome

rRNA

Ribosomal RNA - Makes up ribosome

tRNA

• Transfer RNA - Brings amino acids to the ribosome

• Decodes the mRNA strand into a sequence of amino acids to make a functional protein.

Transcription

Production of RNA (made from DNA molecule)

Translation

• mRNA exits nucleus and travels to ribosome.

• Connects to mRNA binding site next to A site on ribosome

Protein

Macromolecule made of amino acids; speeds up chemical reactions and communicates between cells

Central Dogma

DNA - mRNA (Transcription) mRNA - Protein (Translation)

Ribosomes

Organelle responsible for making proteins

Where does transcription occur?

Inside the nucleus

Where does translation occur?

Cytoplasm and ribosomes

What does DNA contain that is the recipe for proteins?

Genes

How does mRNA know where to start transcribing?

DNA strands contain sections of DNA known as promoter regions at the beginning of their gene sequences — The promoter regions (TATA box) job is to get the attention of RNA polymerase, the enzyme whose job it is to transcribe DNA into mRNA

Methyl Groups

Promoter regions can be silenced by methyl groups, preventing them from being transcribed.

Introns

A type of DNA that stays in the nucleus because it doesn’t code for proteins

Exons

Type of DNA that exits the nucleus because they have the code needed to make a protein

RNA Splicing

Enzymes will cut out introns, so only exons are transcribed into mRNA and carried out of the cell.

Location of ribosomes

• Cytoplasm (all cells)

• Rough ER (Eukaryotes only)

Codon

The mRNA sequence is translated 3 nucleotides at a time. Each section is a …

Anticodon

The complementary tRNA 3 nucleotide sequence

When do mutations occur?

During S-phase

Mutation

Any change in A, T, G, or C when the DNA is copying itself

Some beneficial mutations are

• Sickle Cell Anemia (ONLY BENEFICIAL IN PLACES WITH MALARIA)

• Antibiotic Resistance

• Murray Gray Cows

• HIV Immunity in Humans

- CCR5-delta32 (deletion of 32 base pairs which blocks HIV from entering!)

Harmful Mutations

• Cystic fibrosis: Causes thick mucus to clog lungs and block ducts in digestive organs

• Canavan disease: Brain degenerates

• Turner Syndrome: Females born with only one X chromosome

• Tay-Sachs Disease: Destroys nerve cells in brain and spinal cord

Point Mutation

Substitution

Frameshift Mutation

Insertion or Deletion